Electrodeposited article and method of making the same



Get. 28. 1924.

c.' P. MADSEN ELECTRODEPQSITED ARTICLE AND METHOD OF MAKING THE SAMEOriginal Filed Auz. 15. 1919 5 SECONDS "/7 or oecummamc ygwwng S e H v 5u a??? m m 1 Wm C 0 m 0 C:C. wfl m 70 Patented Oct. 1924.

CHARLES P. MADSEN, OF NEW YORK, Y".

, ASSIGNOR TO MADSENELL CORPORATION,

OF NEW YO'RK, N. Y., A CORPORATION OF NEW YORK.

ELEGTBODEPOSITED ARTICLE AND by electrodeposition. The present inventionaims to provide improved methods of electrodepositing metals, especiallythe ni-ckel metals referred to above, particularly, but not exclusively,in tubular form, and aims also to provide articles, particularly oftubular form, made of such nickel-metals by electrodeposition. I

.By way of example I shall describe herein illustrative embodiments ofthe methods and of the articles of my.invention. In practicing themethod comprising one such illustrative embodiment, I may employ theapparatus diagrammatically illustrated in:

Figure 1 of the'accompanying drawings;

Figure 2 being a diagram illustrating certain time and spacerelationships which may be utilized in practicing said illustrativeembodiment of the method.

I shall describe the method comprising such illustrative embodimentinconnection with the bath and the new nickel described in my copendingapplication, Serial No. 292,794 filed April 26, 1919. In practicingcircular cylindrical cathode 1 mounted for rotation on a shaft 2 whichmay be rotated by any suitable means, not shown.

The cathode may be made of an easily fusible metal, cast about theshaft, if a separable deposit, such as a nickel tube, is desired. Insuch a case the fusible metal core may readily be melted out when thedeposit has reached the desired thickness. If an adherent deposit, suchas a nickel coating, is desired, the object to be coated is suitablysupported on the shaft 2. vThe shaft itself may be supported in stufling'boxes, not shown, placed in the sides I of the vat or tank 3 containingthe bath};-

said method, I may employ a substantially METHOD OF MAKING THE SAME.

Application filed 'August15, 1919, Serial No. 317,656. Renewed January21, 1924.

5, 5 are the anodes which, in the example here given, may consist ofcast nickel. Contact may be maintained with the anodes, by means of theleads 6, 6, attached thereto, and with the cathode by means of the lead7 through the shaft 2.

In practicing the hereindescribed illus trative embodiment of the methodof my invention, I may use an electrodeposition bath of approximatelythe following composition: v

Nickel sulphate, 240 g.

Nickel chloride, 20 g.

Boric acid, 40 g.

Water, 1 liter.

This bath is preferably operated at a temperature of about 130 F. Exceptfor the addition of boric acid, as set forth above, the bath should beneutral.

In order that the electrodeposited metal,

suspension in the bath during electrodeposilVhile the quantity ofhydrate so tion. added may vary within considerable limits, I prefer toadd from about 1 to about 5 grams, generally about 1 gram, of saidcolloidal nickel hydrate to each liter of bath solution.

This colloidal nickel hydrate may be prepared in any suitable manner, aswell known to those skilled in the art, for example, by adding anaqueous solution of caustic soda to an excess of an aqueous solution ofnickel sulphate, and after decanting the supernatant liquid adding thecolloidal nickel hydrate thus produced, with or without washing, to theelectrolyte.

' I find that by adding to the bath certain salts, such as thesulphates, of the alkali .metals, preferably sodium, finely divided orcolloidal nickel hydrate is produced and held in, suspension in the bathduring deposition. This freshly and continuously produced hydratereplenishes the initially added ..,or subsequently generatednickelhydrate"which, during the operation of the bath, aggregates or forother reasons goes out of suspension and drops to the bottom of thebath. Such salts have further beneficial effects and markedly improvethe operation of the bath and the. character of sodium hydroxide thusproduced, by interaction with the nickel salts present in the bath, suchas the nickel sulphate, generates finely divided or colloidal nickelhydrate which remains suspended in the bath. The interaction at the sametime re-generates the sodium sulphate.

The rotating cathode on which the deposit 7 takes place has a portionthereof extending out of the bath into a gaseous medium, preferably ofan oxidizing nature, such as the air. The angular velocity of rotationof the cathode and the portion of the same exposed to the surroundingair should be so chosen that the time during which the cathode and anyportion of the electrodeposited metal carried by it are exposed to theair should be more than what I term the minimum or hydrogendissipationperiod, in order to permit the hydrogen deposited with the metal to bedissipated or removed by contact with the surrounding gaseous medium.Tl'llS minimum or hydrogen dissipation period may readily be determinedby trial and experiment, and is generally greater than about one-half ofa second, usually from one to two seconds. I

The time during which the cathode and any portion of the deposit carriedby it are exposed to the air should not, however, exceed what I term'themaximum or critical or separable deposit period, which, in the case ofnickel, is from about 6 to about 16 seconds. By this I mean that if thedeposit is exposed to the air longer than said period, on restoring thecathode and its deposit to the bath, the succeeding deposit will not beadherent but will separate or be easily separable from the previousdeposit.-

This results in a laminated, weak, metal, a condition which is obviouslyto be avoided where a sound, unitary metal is desired.

The minimum and maximum exposure periods are "ery little, if at all,affected by the variables of electrodeposition determining the rate ofhydrogen formation, the minimum exposure period probably depending uponsurface phenomena such as the surface tension and the maxiand thecurrent density employed, may be varied within rather wide limits. Byvarying these factors the deposition period, and consequently the periodof rotation, may be varied through a considerable range. In the case ofnickel deposition, using the bath mentioned by way of example herein,the period of rotation may be varied from about 30 seconds to about 10minutes.

Such a deposition period should be chosen, dependent upon the variableconditions determining the rate of hydrogen formation,

that the hydrogen generated will be removed by exposing the cathodebefore a suflicient quantity has gathered on any portion of its surfaceand before the hydrogen has remained in contact with any portion of thecathode surface long enough to deleteriously affect the quality of thedeposited metal. lt may here be stated that it is desirable that thedeposition period and, consequently, the period of rotation of thecathode be .kept as long as is consistent with the various factorsreferred to, not only to prevent carrying over too heavy a film ofelectrolyte, as subsequently set forth,-but also because it is foundthat deposition takes place more efliciently at lower speeds ofrotation.

All other conditions being fixed, the oathode should rotate once in aperiod. of time equal to the sum of the exposure and deposition periods,the exposure period being, as already stated, probabl a physicalconstant of the metal, and the epposition eriod being a function of thevariables 0 deposition determining the rate of hydrogen formation. For agiven metal and for a, given bath operating under given conditions, thecathode will, therefore, rotate once during a substantially constantperiod, no matter what its diameter and, therefore, its peripheral speedmay be.

There is, however, an upper limit to the angular velocity and,therefore, to the eripheral speed of the rotating cathode, ecause ifsuch angular velocity and peripheral speed are too high, too great alayer of electrolyte will be carried over by the oathode onto theexposed portion of the same, with a consequent prevention, in part atleast, of the proper escape of the hydrogen from the deposit. In such acase the factors determining the rate of hydrogen formation should bevaried so as to reduce such rate to a point such that the rate ofrotation of the cathode may be correspondingly reduced below the upperlimit referred to. I find that the bath herein mentioned by way ofexample and kept almost absolutely neutral, and operating at atemperature of 130 F. with a current density of 200 amperes per squarefoot, the rate of rotation desirable is once in about 5 to 10 minutes;While if the bath is slightly acid the desirable rate of rotation isonce in about 1 to 2 minutes.

It will be apparent from the foregoing, discussion that the ratio ofexposure and deposition periods determines the ratio of the exposed andsubmerged portions of the cathode. It will also be apparent from theforegoing discussion that witha given metal and with a given bathoperated under given conditions, this ratio of exposed and submerged orunexposed portions of the cathode surface will be constant, no matterwhat the diameter of the cathode may be, the rate of rotation of thecathode also being constant under such given conditions, while theperipheral speed will of course vary within very wide limits dependenton the diameter of the cathode.

To more specifically illustrate the time and space relationshipspreviously discussed, as applied to the hereindescribed illusirativeembodiment of my invention, I shall choose five (5 seconds (which ismore than the usual minimum and less than the usual maximum periods) asthe exposure period or time during which any part of theelectrodeposited surface may be exposed to the air at any one time. Ishall choose thirty (30) seconds as the deposition period or the timeduring which the cathode may remain within the bath between successiveexposures. This will give thirty (30) plus five (5) or thirty five (35)seconds as. the time of one complete rotation of the cathode, which iswithin the range of the usual periods of rotation. The ratioof5to35islto7,andcf30to35is6to 7 so that oneseventh part of thecathodesurface will be exposed to the air, and sixsevenths ofsaid surface willbe immersed in the bath. This relation is diagrammatically illustratedin Figure 2. Assuming, by way of example, that the average outsidediameter for the" cathode surface is seven (7) inches, this diameterwill correspond to a circumference of about twentytwo (22) inches, andwith the cathode rotating once every thirty five (35) seconds, this willcorrespond to a peripheral velocity of the cathodesurface of aboutthirty eight (38) inches, or about three (3) feet, per

minute. Other factors being the same, the peripheral velocity, which isin itself not of controlling importance in 'connectiou with the presentinvention, w ill be proportional to the diameter of the rotatingcathode, that is, it will be twice three (3), .or about six (6) feet perminute for acathode fourteen (14) inches in diameter and one half ofthree (3) or about one and a half (1%) feet per minute for a cathodethree and one half (3%) inches in diameter, in the example here given.

, In certain cases I find that better results are obtainable if thecathode is rotated intermittently, instead of continuous- 1y, stillhaving regard for the various time and space factors referred to inconnection with the above described embodiment.

Thatis, instead of rotating the cathode at 'a uniform rate, the cathodemay be retatedintermittently so as to expose suethe electro-depositionmay be carried out by passing the current through a bath solutioncontained entirely within the hollow object. If the object is open atone or both ends, as where it is a pipe intended to be coated on theinside, either or both ends may be closed by means of plugs. An anode,in the form of a rod, may be passed through the plugs and the bathsolution may be connected with a reservoir containing further quantitiesof electrolyte by means of a plurality of tubes also passing through theplugs. The deposition may be carried out by only partially filling thetube with solution and then rotating the same about a substantiallyhorizontal axis, ohserving time and space relationships analogous tothose that have already been set forth in connection with the embodimentfirst described above. The provision of the reservoir enables theelectrolyte to be circulated through the tube whose interior is beingcoated, thereby constantly providing fresh electrolyte of properstrength.

The resulting product, in the illustrative embodiment) first set forthabove, comprises an unworked, seamless, electrodeposited nickel tube,the metal of which is dense,

reguline, homogeneous, malleable and ductile. a

The nickel of which this tube is made is to be differentiated from theusual electrodeposited nickle in that it is substantiah .cessivefractions of the same to theair'for iii) nickel which is pitted andporous, has a large hydrogen content, and is brittle and unworkable.

The nickel herein described difi'ers in' 5 character from the nickelobtained by the usual metallurgical processes in that my new nickel isfree-from the usual poisons such as sulphur, silicon, arsenic, carbon,carbides, oxygen and other gases, and oxide- 1 containing compounds,generally present in metallurgical nickel, and rendering the sameimperfect and diflicult to work.

. My new nickel is to be further difl'erentiated from the ordinarymetallurgical nickel in that it has a finer and more even grain thansuch metallurgical nickel. It is also considerably purer. than suchmetallurgical nickel, resists chemical action better, and has a highermelting point.

my new nickel and the ordinary metallurgical nickel is shown b the factthat the film of oxide formed by eating my new nickel in an oxidizingatmosphere is thinner, finer in texture, and more adherent and flexiblethan the oxide coating formed by similar treatment of ordinarymetallurgical nickel. Furthermore, such oxide coating in the case of mynew nickel is of a difierent color,

' generally yellow to brown, while the oxide 40 set forth for thedeposition of nickel and of cobalt in the desired condition and having 4the desired properties may be employed.

It is of course, to be understood that the invention is not to belimited to the s ecific illustrative embodiments thereof, hereindescribed for purposes of illustration only.

It is also to be understood that the applicant does not wish to have theinvention or the appended claims in any way limited by any rticulartheor of operation which he may now hold or which may be suggested bythe fore oi detailed description.

' at claim isz":

1. A method of electrodepositing metals 'which comprises rotating thecathode at such an angular velocity and with such'a portion of the sameexposed to a aseous'medium that successive portions 0 the electrode.-

' posited metal will be ex' to said medium more than a pre eterminedmini- ,mum eriod so as to permit the hydr n in the I t t ittd metal tobe dissipated. oge

A methcd of electrodepositmg metals which comprises rotating the cathodeat such 05 an angular velocity and with such a portion A furtherdifference in character between of the same exposed to a gaseous mediumthat successive portions of the electrodeposited metal will be exposedto said medium more than a predetermined minimum period, so as to permitthe hydrogen in the deposited metal to be dissipated, but less than apredetermined maximum period, so as to prevent the successive depositsfrom being separable.

3. A method of electrodepositing nickel metals which comprises rotatingthe oathode at such an angular velocity and with such a portion of thesame exposed to a gaseous medium that successive ortions of theelectrodeposited metal will be exposed to said medium more than apredetermined minimum period, so as to permit the hydrogccn in thedeposited metal to be dissiate P 4. A method of electrodepositing nickelmetals which comp-rises rotating the cathode at such an angular velocityand with such a portion of the same exposed to a gaseous medium thatsuccessive. portions of the electrodeposited metal will be exposed tosaid medium more than a predetermined minimum period, so as to permitthe hydro en in the deposited metal to be dissipated, iut less than apredetermined maximum pe riod, so as to prevent the' successive depositsfrom being separable.

5. A method of electrodepositing nickel which comprises rotating thecathode at such an angular velocity and with such a portion of the sameexposed to a aseous medium that successive portions of t eelectrodeposited nickel will be exposed to said medium more than apredetermined minimum period, so as to permit the hydrogen in thedeposited nickel to be dissipated.

6. A method of electrodepositing nickel which comprises rotating thecathode at suchan angular velocity and with such a portion of the sameexposed to a gaseous medium that-successive portions of theelectrodeposited nickel will be exposed to said medium more than apredetermined minimum riod, so as to permit the hydrogen in the epositednickel to be dissipated, ut

less than a predetermined maximum period, so as to prevent thesuccessive'deposits from being separable.

7. A method of electrodepositing metals which comprises rotating thecathode at such an angular velocity and with such a portion of the sameexposed to a gaseous medium that successive portions of theelectrodeposited metal will be exposed to said medium less than apredetermined maximum period, so as to prevent the successive depositsfrom being separable.

8. A method of electrodepositing metals which comprises rotating thecathode at such an angular velocity. and with such a portion of the sameexposed" to the air that 9. A methodof electrodepositingmetals whichcomprises rotating the cathode 'at' such an angular velocity and withsuch a portion of the same exposed to the air that successive portionsof the electrodeposited metal will be exposed to the air more than apredetermined minimum period, so as to permit the hydrogen in thedeposited metal to be dissipated, but less than apredeter mined maximumperiod, so as to prevent the successive deposits from being separable,the angular velocity of rotation of the cathode not being suflicientlygreat to prevent the film of bath liquid initially carried by thesuccessive exposed portions ofthe rotating cathode from freely jflowingoff from such portions during the successive exposure periods.

10. A method of electrodepositing nickel metals which comprises rotatingthe cathode at such an angular velocity and with such a portion of thesame exposed 'to the air that successive portions of theelectrodeposited metal will be exposed to .the air more than apredetermined minimum period, so as to permit the hydrogen in thedeposited metal to be dissipated, the angular velocity of rotation ofthe cathode not being sufiiciently great to prevent the film of bathliquid initially carried by the successive exposed portions of therotating cathode from freely flowing of from. such' portions during thesuccessive exposure periods.

11. A method of electrodepositing nickel metals which comprises rotatingthe cathode at such an angular velocity and with such a portion of thesame exposed to the air that successive portions of the electi cularconditions employed.

trodeposited metal will be exposed to the air more than a predeterminedminimum period, so as to permit the hydrogen in the deposited metal tobe dissipated, but less than a predetermined maximum period,

so as to prevent the successive deposits from being separable, theangular velocity of rotation of the cathode not being sufficiently greatto prevent the film of bath liquid initially carried by the successiveexposed portions of the rotating cathode from freely flowing oil fromsuch portions during the successive exposure periods.

12. As an article ofmanufacture, a seamless electrodeposited tubeofunworked, dense, malleable nickel-metal, substantially free from pores,pits and hydrogen.

13. As. an article of manufacture, aseamless electrodeposited tube ofunworked, dense, malleable nickel, substantially free from pores, pitsand hydrogen,

14. A method of electrodepositing metals on a rotating cathode whichcomprises maintaining a predetermined portion of the :cathode surfaceexposed to a gaseous medium, the ratio of the exposed to the unexposedportions of the cathode surface being, substantially equal to the ratiobetween the exposure riod for the particular metal being deposited andthe deposition period for the particular bath used under the par- 15. Amethod of electrodepositing metals which comprises rotating the cathodeat such an an ular velocity and with. such'a portion of t e same exposedto a gaseous medium that successive portions of the electrodepositedmetal will be exposed to said medium more than a predetermined minimumperiod, so as to permit the hydrogen in the deposited metal to bedissipated, the deposition period being less than a period which, underthe particular conditions involved in the deposition would prevent thehydrogen in the deposit from being freely dissipated during the exposureperiod.

In testimony whereof, I have signed my name to this specification this7th day of August, 1919. A I

, CHARLES P. MADSEN.

